+var global = require('../internals/global');
+var call = require('../internals/function-call');
var isObject = require('../internals/is-object');
+var isSymbol = require('../internals/is-symbol');
+var getMethod = require('../internals/get-method');
+var ordinaryToPrimitive = require('../internals/ordinary-to-primitive');
+var wellKnownSymbol = require('../internals/well-known-symbol');
+
+var TypeError = global.TypeError;
+var TO_PRIMITIVE = wellKnownSymbol('toPrimitive');
// `ToPrimitive` abstract operation
// https://tc39.es/ecma262/#sec-toprimitive
-// instead of the ES6 spec version, we didn't implement @@toPrimitive case
-// and the second argument - flag - preferred type is a string
-module.exports = function (input, PREFERRED_STRING) {
- if (!isObject(input)) return input;
- var fn, val;
- if (PREFERRED_STRING && typeof (fn = input.toString) == 'function' && !isObject(val = fn.call(input))) return val;
- if (typeof (fn = input.valueOf) == 'function' && !isObject(val = fn.call(input))) return val;
- if (!PREFERRED_STRING && typeof (fn = input.toString) == 'function' && !isObject(val = fn.call(input))) return val;
- throw TypeError("Can't convert object to primitive value");
+module.exports = function (input, pref) {
+ if (!isObject(input) || isSymbol(input)) return input;
+ var exoticToPrim = getMethod(input, TO_PRIMITIVE);
+ var result;
+ if (exoticToPrim) {
+ if (pref === undefined) pref = 'default';
+ result = call(exoticToPrim, input, pref);
+ if (!isObject(result) || isSymbol(result)) return result;
+ throw TypeError("Can't convert object to primitive value");
+ }
+ if (pref === undefined) pref = 'number';
+ return ordinaryToPrimitive(input, pref);
};